A Software Tool Developed for Simplified Numerical Modeling of Thermal Conduction around Distorted Geothermal Boreholes

2017 ◽  
Vol 21 ◽  
pp. 529-534
Author(s):  
Augustin Leiter
Keyword(s):  
Mathematical Model ◽  
Numerical Modeling ◽  
Thermal Properties ◽  
Thermal Conduction ◽  
Numerical Models ◽  
Software Tool ◽  
Geothermal System ◽  
Drilling Process ◽  
Specialized Software ◽  
Simplified Mathematical Model

The geometric characteristics of multiple geothermal boreholes organized in a geothermal system affect its thermal efficiency. The location of boreholes and their verticality and straightness is often distorted during drilling process. This distortion then degrades thermal properties of such a system. To study this phenomenon a specialized software tool was developed for numerical modeling based on a simplified mathematical model. This paper describes software tool briefly and presents some initial numerical models of basic borehole arrangements solved by this tool. Paper also contains a verification calculated by specialized software FEFLOW.

scholarly journals Development of simplified mathematical model of P-88 recovery boiler for operating modes at loads near the nominal

Vestnik IGEU ◽  
2021 ◽  
pp. 5-13
Author(s):  
B.L. Shelygin ◽  
S.A. Pankov ◽  
G.V. Ledukhovsky
Keyword(s):  
Mathematical Model ◽  
Power Unit ◽  
Combined Cycle ◽  
Operating Conditions ◽  
Software Systems ◽  
Specialized Software ◽  
Combined Cycle Plant ◽  
Calculation Results ◽  
Recovery Boiler ◽  
Simplified Mathematical Model

To improve the design of the elements of combined-cycle plants, and their structural and mode optimization, mathematical models are required. These models show energy efficiency indicators of the equipment under changing operating conditions. Modeling of recovery boilers is traditionally carried out with the application of specialized software systems that implement submodels of thermal-hydraulic calculations of the elements of the boiler water-steam and gas paths. This approach makes it difficult to solve practical tasks, since it requires licensed software and appropriate qualifications of an engineer. The current direction of solving this problem is statistical processing of the results of calculation data obtained with the application of specialized software systems, and development of a simplified mathematical model in the form of regression dependencies of boiler performance on variable parameters. In this study, the problem is solved in relation to the P-88 boiler of the combined-cycle plant-325 power unit in the load range near the nominal one. The initial mathematical model is developed with the application of the software package “TRAKT” designed for verification and engineering design of boilers. The simplified mathematical model is based on the methods of regression analysis of statistical data. The accuracy of the model is estimated based on the operational data of the combined-cycle plant -325 power unit. The authors have developed the mathematical model of the P-88 recovery boiler, which allows to determine the main performance indicators of the boiler when the electric power of the gas turbine and the outdoor air temperature are changing at the loads near the nominal value. The performance indicators are determined without application of specialized software for design calculation of the boiler. The accuracy of the initial mathematical model implemented in the software package “TRACT” is characterized by deviation of the calculation results data from the operational data in the corresponding modes of no more than 2 %. The additional uncertainty value introduced into the calculation results data does not exceed 1,5 % when we transfer from the initial mathematical model to the simplified one. The resulting mathematical description will allow solving the problems of mode optimization and evaluating the efficiency of the recovery boiler and the power unit under changing operating conditions.

scholarly journals Two-Dimensional Numerical Modeling of Flow in Physical Models of Rock Vane and Bendway Weir Configurations

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 458
Author(s):  
Drew C. Baird ◽  
Benjamin Abban ◽  
S. Michael Scurlock ◽  
Steven B. Abt ◽  
Christopher I. Thornton
Keyword(s):  
Numerical Modeling ◽  
Physical Model ◽  
Numerical Models ◽  
Hydraulic Performance ◽  
Physical Models ◽  
Protection Measures ◽  
Design Engineers ◽  
Model Study ◽  
Study Results ◽  
Wide Range

While there are a wide range of design recommendations for using rock vanes and bendway weirs as streambank protection measures, no comprehensive, standard approach is currently available for design engineers to evaluate their hydraulic performance before construction. This study investigates using 2D numerical modeling as an option for predicting the hydraulic performance of rock vane and bendway weir structure designs for streambank protection. We used the Sedimentation and River Hydraulics (SRH)-2D depth-averaged numerical model to simulate flows around rock vane and bendway weir installations that were previously examined as part of a physical model study and that had water surface elevation and velocity observations. Overall, SRH-2D predicted the same general flow patterns as the physical model, but over- and underpredicted the flow velocity in some areas. These over- and underpredictions could be primarily attributed to the assumption of negligible vertical velocities. Nonetheless, the point differences between the predicted and observed velocities generally ranged from 15 to 25%, with some exceptions. The results showed that 2D numerical models could provide adequate insight into the hydraulic performance of rock vanes and bendway weirs. Accordingly, design guidance and implications of the study results are presented for design engineers.

scholarly journals The use of simulation modelling for determining the capacity of railway lines in the Czech conditions

2020 ◽  
Vol 10 (1) ◽  
pp. 224-231
Author(s):  
Erik Tischer ◽  
Petr Nachtigall ◽  
Jaromír Široký
Keyword(s):  
Czech Republic ◽  
Traffic Flow ◽  
Software Tool ◽  
Simulation Modelling ◽  
Energy Performance ◽  
Simulation Software ◽  
The Czech Republic ◽  
Railway Line ◽  
Specialized Software ◽  
Railway Infrastructure

AbstractSimulation modelling is one way to determine the capacity of railway lines. The specialized software tool OpenTrack was used for simulation. The aim of this paper was to find out whether the OpenTrack simulation software can be used for the calculation of headway, and to compare the results with the methodology of the Railway Infrastructure Administration (SŽDC). Using the software tool, a detailed transport network model can be created including all its important characteristics. The simulation follows the movements and behaviour of trains with predefined parameters on the modelled railway line. OpenTrack allows for monitoring a range of parameters including not only train delays, train conflicts and train traffic flow, but also for instance train energy performance and headways. During the first stage of work with OpenTrack, a simulation model was created, not reflecting any existing infrastructure but including parameters typical of railway lines in the Czech Republic, such as the configuration of gridirons, length of station tracks, size of block sections, etc. This model was subsequently used for the simulation of type train set journeys, and a headway calculator was used for the calculation of headway values. These values were compared with the methodology used by the Railway Infrastructure Administration. The paper is concluded by the comparison of the above mentioned approaches.

Research on Flux Damping Control Strategy of DFIG during Grid Voltage Dips

2015 ◽  
Vol 713-715 ◽  
pp. 756-759
Author(s):  
Xu Guang Zhang ◽  
Zhen Xie
Keyword(s):  
Mathematical Model ◽  
Control Strategy ◽  
Grid Voltage ◽  
Damping Control ◽  
Simulink Simulation ◽  
Voltage Dips ◽  
Simulation Results ◽  
Stator Flux ◽  
Natural Component ◽  
Simplified Mathematical Model

A flux damping control strategy was proposed to accelerate the decay of stator flux and restrain stator, rotor current and torque oscillation caused by grid voltage dips. Firstly, this paper analyzes the simplified mathematical model of DFIG during symmetrical voltage dips. Then, the mechanism of flux damping control strategy to restrain stator, rotor current oscillation and increase flux damping was analyzed. The flux damping control strategy can increase the damping of stator side, which accelerates the decay of the stator flux natural component and improve the dynamic LVRT performance of DFIG. The correctness and effectiveness of this method is verified by MATLAB/Simulink simulation results.

Thermal Analysis of Expressway Considering Wind Effect

2013 ◽  
Vol 419 ◽  
pp. 895-904
Author(s):  
X. Cao ◽  
H. Miyashita ◽  
T. Kako ◽  
Z. Zhang ◽  
B. Song
Keyword(s):  
Mathematical Model ◽  
Thermal Analysis ◽  
Thermal Conduction ◽  
Computer Calculation ◽  
Basic Mechanism ◽  
Weather Data ◽  
Wind Effect ◽  
Fortran Language ◽  
Explicit Finite Difference ◽  
Explicit Finite Difference Method

This paper reports a method of thermal analysis of expressway and the results of analysis of four expressways currently used in Japan. The authors built a mathematical model based on the principle of thermal conduction. For the boundary conditions in this mathematical model the influence of solar radiation, wind and air temperature etc. are taken into consideration. Explicit finite difference method is used in the analysis. The authors made an analysis program in Fortran language. Four main expressways distributing from the northern to the southern in Japan are chosen as the objects of this study. The observed weather data of the hottest days experienced by these expressways during the past 30 years is input into the computer calculation. The basic mechanism of expressway temperature change and effect factors are illuminated. The results are reported and discussed.

scholarly journals Numerical modeling of the hydraulic impact of riparian vegetation

2018 ◽  
Vol 44 ◽  
pp. 00194
Author(s):  
Krzysztof Wolski ◽  
Tomasz Tymiński ◽  
Grzegorz Chrobak
Keyword(s):  
Numerical Modeling ◽  
Riparian Vegetation ◽  
Water Surface ◽  
Numerical Models ◽  
Three Dimensional ◽  
Careful Examination ◽  
Impact Structure ◽  
Hydraulic Impact ◽  
Vegetation Zones ◽  
Maximal Shear Stress

This paper presents results of numerical modelling of riverbed segment with riparian vegetation performed with use of CCHE2 software. Vegetation zones are places where dynamic of water flow increases. Therefore, there is a need of careful examination of hydraulic impact structure of such zones. Accurate research is necessary and should be performed with use of physical or numerical models, two or three dimensional. Paper presents distribution of velocity and area of water surface for two variants of vegetation deposition acquired in CCHE2D software and modelled for riverbed with distinctive riparian vegetation. Results point to significant (30–40%) increase of maximal velocities in riverbed with riparian vegetation, while directly near the vegetation there were zones with very low velocities. Local damming occurs before vegetal zone. Maximal shear stress in zones with increased velocity is significantly augmented compared to conditions with no vegetation, which can cause more intensive erosion in those zones

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